Index: sys/dev/uart/uart_dev_ns8250.h
===================================================================
--- sys/dev/uart/uart_dev_ns8250.h
+++ sys/dev/uart/uart_dev_ns8250.h
@@ -41,6 +41,12 @@
 	uint8_t		ier_mask;
 	uint8_t		ier_rxbits;
 	uint8_t		busy_detect;
+
+	/*
+	 * Save LSR register because error bits are cleared on read. They must
+	 * be saved whenever the register is read but not immediately used.
+	 */
+	uint8_t		lsr_saved_flags;
 };
 
 extern struct uart_ops uart_ns8250_ops;
Index: sys/dev/uart/uart_dev_ns8250.c
===================================================================
--- sys/dev/uart/uart_dev_ns8250.c
+++ sys/dev/uart/uart_dev_ns8250.c
@@ -71,6 +71,8 @@
 ns8250_clrint(struct uart_bas *bas)
 {
 	uint8_t iir, lsr;
+	struct ns8250_softc *ns8250 = (struct ns8250_softc *)bas;
+	ns8250->lsr_saved_flags = 0;
 
 	iir = uart_getreg(bas, REG_IIR);
 	while ((iir & IIR_NOPEND) == 0) {
@@ -138,6 +140,9 @@
 	int delay, limit;
 
 	delay = ns8250_delay(bas);
+    
+	struct ns8250_softc *ns8250 = (struct ns8250_softc *)bas;
+	ns8250->lsr_saved_flags = 0;
 
 	if (what & UART_DRAIN_TRANSMITTER) {
 		/*
@@ -190,8 +195,11 @@
 	fcr = FCR_ENABLE;
 	if (what & UART_FLUSH_TRANSMITTER)
 		fcr |= FCR_XMT_RST;
-	if (what & UART_FLUSH_RECEIVER)
+	if (what & UART_FLUSH_RECEIVER) {
 		fcr |= FCR_RCV_RST;
+		struct ns8250_softc *ns8250 = (struct ns8250_softc *)bas;
+		ns8250->lsr_saved_flags = 0;
+	}
 	uart_setreg(bas, REG_FCR, fcr);
 	uart_barrier(bas);
 }
@@ -203,6 +211,9 @@
 	int divisor;
 	uint8_t lcr;
 
+	struct ns8250_softc *ns8250 = (struct ns8250_softc *)bas;
+	ns8250->lsr_saved_flags = 0;
+
 	lcr = 0;
 	if (databits >= 8)
 		lcr |= LCR_8BITS;
@@ -333,8 +344,10 @@
 static int
 ns8250_rxready(struct uart_bas *bas)
 {
-
-	return ((uart_getreg(bas, REG_LSR) & LSR_RXRDY) != 0 ? 1 : 0);
+	uint8_t lsr = uart_getreg(bas, REG_LSR);
+	struct ns8250_softc *ns8250 = (struct ns8250_softc *)bas;
+	ns8250->lsr_saved_flags = lsr;
+	return ((lsr & LSR_RXRDY) != 0 ? 1 : 0);
 }
 
 static int
@@ -344,10 +357,16 @@
 
 	uart_lock(hwmtx);
 
-	while ((uart_getreg(bas, REG_LSR) & LSR_RXRDY) == 0) {
+	uint8_t lsr = uart_getreg(bas, REG_LSR);
+	struct ns8250_softc *ns8250 = (struct ns8250_softc *)bas;
+	ns8250->lsr_saved_flags = lsr;
+
+	while ((lsr & LSR_RXRDY) == 0) {
 		uart_unlock(hwmtx);
 		DELAY(4);
 		uart_lock(hwmtx);
+		lsr = uart_getreg(bas, REG_LSR);
+		ns8250->lsr_saved_flags = lsr;
 	}
 
 	c = uart_getreg(bas, REG_DATA);
@@ -683,6 +702,8 @@
 	ipend = 0;
 	if (iir & IIR_RXRDY) {
 		lsr = uart_getreg(bas, REG_LSR);
+		ns8250->lsr_saved_flags = lsr;
+
 		if (lsr & LSR_OE)
 			ipend |= SER_INT_OVERRUN;
 		if (lsr & LSR_BI)
@@ -894,12 +915,18 @@
 ns8250_bus_receive(struct uart_softc *sc)
 {
 	struct uart_bas *bas;
+	struct ns8250_softc *ns8250 = (struct ns8250_softc*)sc;
 	int xc;
 	uint8_t lsr;
 
 	bas = &sc->sc_bas;
 	uart_lock(sc->sc_hwmtx);
-	lsr = uart_getreg(bas, REG_LSR);
+	if (ns8250->lsr_saved_flags != 0) {
+		lsr = ns8250->lsr_saved_flags;
+	} else {
+		lsr = uart_getreg(bas, REG_LSR);
+	}
+	ns8250->lsr_saved_flags = 0;
 	while (lsr & LSR_RXRDY) {
 		if (uart_rx_full(sc)) {
 			sc->sc_rxbuf[sc->sc_rxput] = UART_STAT_OVERRUN;